Electron discharge device



May 30, 1950 Y H. G. ANDERSON 2,509,951

ELECTRON DISCHARGE DEVICE Filed Jan. 22, 1947 hun" Patented May 30, 1950 ELECTRON DISCHARGE DEVICE Homer G. Anderson, Newtonville, Mass., assig'nor to Raytheon Manufacturing Company, Newton, Mass., a corporation of Delaware Application January 22, 1947, Serial No. 723,510

7 Claims.

This invention relates to electron discharge devices and more particularly to a vnovel structure for supporting the cathode heating means there- The main object of the present invention is to provide means for supporting the cathode heating means Without resorting to the use of insulators to accomplish the aforesaid object.

The above and many other objects will become apparent as the illustrative embodiment of the present invention is described and will be readily observable by reference to the accompanying drawing in which:

Fig. 1 is a vertical section through an electron discharge device embodying an illustrative embodiment of the present invention;

Fig. 2 illustrates in greater detail the illustrative embodiment of the present invention;

Fig. 3 presents a vertical section of the lead-in assembly for said electron discharge device; and

Fig. 4 is a view of Fig. 2 taken along line t-ft Referring now more particularly to Fig. l, the reference numeral I represents a cylindrical envelope of an electron discharge device of the So-called magnetron type, hermetically sealed at both ends by a pair of caps II and I2. Adjacent said caps are the usual pole pieces IIA and IZA associated with this type of electron discharge device. Said envelope and caps may be and preferably are made of copper. Upon the inner surface of said envelope there is provided a central, circular projection I3 to which are attached, as by soldering for example, a plurality of suitably spaced, radially disposed metal plates I4, the inner ends of which constitute anode faces. Said anode faces cooperate with a cathode structure I5 supported substantially centrally of said anode faces, said cathode being preferably of the indirectly-heated, thermionic type.

The cathode I5,` see Fig'. 2, comprises, in addition to a sleeve |15 of nickel or other conductive material, a screen-like member l1 substantiany surrounding said sleeve for the purpose of properly 'supporting a suitable electron-emissive coating I8 of barium and strontium or other electronemissive material, and a helically wound electrically insulated heater Wire I9. Said heater Wire is wound in a manner described in a copending application of Homer G. Anderson, Serial No. 562,334, filed November 7, 1944, now Patent No. 2,439,786, dated April 20,- 1948. HOW- ever, in accordance with the present invention, said heater Wire is supported within the coniines of the conductive sleeve I-S, the end 20 of said heater wire being attached, for example, by

Welding same Within and to the lower portion of said conductive sleeve IB.

The opposite end 2| of said heater Wire I9 is connected to a lead-in conductor 22 which enters the envelope Ill through a glass seal 23 mounted at the outer end of a conducting pipe 24 which extends through the Wall of said envelope II) and is hermetically secured therein. A second leadin conductor 25 is sealed through a similar glass seal 23 mounted at the outer end of a second conducting pipe 24.

Said last-named lead-in conductor 25 is attached, as by Welding, intermediate a pair of substantially parallel members 2@ and 21, see Fig. 4, one of each of the respective ends thereof terminating in a substantially U-shaped configuration 2S and 29 and extending perpendicularly from said parallel members. The free ends of said U-shaped portions of the parallel members are attached by suitable means to the edge of a substantially circular metal shield member 30, constructed in accordance with the description oi aforesaid copending application of Homer G. Anderson. Said shield member is one of a pair 3-3I of such members.

The shield members 3B--3I are electrically connected, respectively, by means of metal supports 32 to the inner vertical sides of a pair of dish-like metal members 33-34 attached to and within the opposite ends of said conductive sleeve 45. Both 'of said last-named members are provided with perforaticns 35-36, see Fig. 2, in the center thereof. The perforation 36 provides means for egress of the heater wire end 2|., sufficient space being provided between the shield member 3| and the dish-like member 34 for the passage of the end 2| of said heater wire to the lead-in conductor 22. Connection of the end of said heater wire to the conductor 22 may be made by fitting a tubular member 31, for eX- ample, of platinum, over the heater wire end 2|, :flattening the opposite end of said tubular member and attaching said iiattened portion to the lead-in conductor 22 by welding or other suitable means.

Fig. 2 illustrates more clearly the manner in which said tubular member 31 is attached intermediate the heater Wire and the lead-in conductor 22. A tubular member 3B, one end of which is terminated in a spade-like formation 39, provides the means for supporting the cathode structure I5 at the upper end thereof, said upper end being so designated with respect to the drawing, by attaching said spade-like portion 39 to the shield member 3|. An insulating sleeve 40, preferably of ceramic material, is disposed Within said tubular member 38 and fills substantially the entire length thereof, and surrounds the lead-in conductor 22. One end of said insulating sleeve abuts a shoulder lil integral with said lead-in conductor. This arrangement serves to center the lead-in conductor 22 with respect to the tubular member 38 and also insulates said lead-in conductor from the heater wire with respect to the end 2l thereof. A glass bead 42, fused around the lead-in conductor 22 and tubular member 38, serves to maintain said tubular member rigidly in place.

Fig. 3 is a cross-sectional view of the lead-in assembly and illustrates the manner in which the reentrant stem A3 maintains the lead-in conductor 22 in coaxial alignment with the conducting pipe 24. Positioned intermediate said reentrant stem 43 and the glass bead 42 is a metal hollow member M surrounding the lead-in conductor 22. One end of said hollow member is firmly affixed, as by soldering, to the lead-in conductor to provide a radio-frequency choke, the space between said hollow member 44 and the length thereof being sufficient to perform the aforesaid function. With the exception of the tubula1 member 3B and its cooperative insulating sleeve 40, together with the particular arrangement provided for connecting said lastnamed members to the cathode structure I5, the lead-in conductor 25 is similarly supported. A flexible lead 45 is suitably attached to the opposite end of said lead-in conductor 22, and a similar arrangement, not shown, provided for the second-named lead-in conductor 25, to furnish conducting means for any source of heater wire current.

As pointed out previously, Fig. 4 illustrates a view of the shield member 30 taken along line 4-4 of Fig. 2 and shows the particular arrangement for connecting the lead-in conductor 25 to said shield member 30.

The illustrative embodiment of the present invention as above described provides a very simple means for supporting the cathode structure I5 in addition to providing means for conducting heater current to said heater wire I9 without the necessity of utilizing electrical insulating means in the immediate vicinity of said heater wire. This arrangement obviates any possibility of contamination of the cathode by the release of gases from such insulating means due to the proximity thereof to the cathode heating means. Furthermore, the release of gases, for example, such as oxygen, tend to reduce the hardness of the electron discharge device, in this par# ticular embodiment a so-called magnetron. This type of electron discharge device utilizes a very high anode voltage and operates in the microwave spectrum. At such frequencies, the introduction of gases within the envelope Il) tends to alter the dielectric constant therein with a consequent change of the desired frequency in a manner familiar to those versed in this particular art.

A further feature of the present invention makes it possible to utilize thoria coated cathodes. Since this type of coated cathode requires temperatures of the order of 1200 to 1400 centigrade for satisfactory operation, the present invention is adapted to take advantage of the highly electron-emissive properties of thoria coated cathodes.

The embodiment of this invention which has been illustrated and described has been selected for the purpose of setting forth the principles involved. It will be obvious, however, that the in vention may be modified to meet various conditions which may be encountered in different specic uses, and it is, therefore, intended to cover by the appended claims all such modiiications which fall within the spirit and scope of this invention.

What is claimed is:

1. An electron discharge device comprising: an envelope containing a cathode and an anode adjacent thereto; a shield member secured to one end of said cathode; heating means within said cathode; a lead-in conductor connected to said heating means; means, carried by said lead-in conductor and attached to said shield member, supporting said cathode; and means, also carried by said lead-in conductor, insulating said lead-in conductor from said supporting means.

2. An electron discharge device comprising: an envelope containing a cathode and an anode adjacent thereto; a shield member secured to one end of said cathode; a heater wire within said cathode; said Wire being attached at one end to said cathode, the other end thereof being free; a lead-in conductor connected to the free end of said heater wire; means, carried by said lead-in conductor and attached to said shield member, supporting said cathode; and means insulating said lead-in conductor from said supporting means.

3. An electron discharge device comprising: an envelope containing a cathode and an anode adjacent thereto; shield members secured to the ends of said cathode; heating means within said cathode; a lead-in connected to said heating means; means, carried by said lead-in conductor and attached to one of said shield members, supporting said cathode and means, also carried by said lead-in conductor, insulating said lead-in conductor from said supporting means.

4. An electron discharge device comprising: an envelope containing a cathode and an anode adjacent thereto; shield members disposed intermediate the respective ends of said cathode and said envelope; electrically conductive means supporting said shield members adjacent the respective ends of said cathode; a heater Wire for said cathode, one end thereof being connected to one end of said cathode and the other end thereof being free; a plurality of lead-in conductors, one 'of said shield members and the other of which is connected to the free end of said heater wire; means, carried by said last-named lead-in conductor and attached to the other of said shield members, supporting said cathode; and means insulating said last-named lead-in conductor from said supporting means.

5. An electron discharge device comprising: an envelope containing a cathode and an anode adjacent thereto; a shield member secured to one end of said cathode; a heater wire disposed within said cathode, one end of said heater Wire being connected to one end of said cathode and the balance being electrically insulated from said cathode; a lead-in conductor connected to the free end of said heater wire; means, carried by said lead-in conductor and attached to said shield member, supporting said cathode; and means in# sulating said lead-in conductor from said supporting means.

6. An electron discharge device comprising: an envelope containing a cathode and an anode adjacent thereto; shield members disposed intermediate the respective ends of said cathode and said envelope; electrically conductive means supporting said shield members adjacent the respective ends of said cathode; a heater wire disposed Within said cathode, one end of said heater wire being connected to one end of said cathode and the balance being electrically insulatedfrom said cathode; a plurality of lead-in conductors, one of which is connected to said cathode; means, carried by the second of said lead-in conductors and attached to one of said shield members, for supporting said cathode; and means insulating said last-named lead-in conductor from said supporting means.

7. An electron discharge device comprising: an envelope containing a cathode and an anode adjacent thereto; shield members disposedintermediate the respective ends of said cathode and said envelope; electrically conductive means supporting said shield members adjacent the respective ends of said cathode; a heatel` wire disposed within said cathode, one end of said heater wire being connected to one end of said cathode and the balance being electrically insulated from said cathode; a plurality of lead-in conductors,

REFERENCES CITED The following references are of record in the le of this patent:

UNITED STATES PATENTS y Number Name Date 2,406,276 White Aug. 20, 1946 2,406,277 Bondley Aug. 20, 1946 2,408,239 Spencer Sept. 24, 1946 2,414,581 Buritz et al. Jan. 21, 1947 2,416,298 Fisk Feb. 25, 1947 2,418,117 Hale et al Apr. 1, 1947 2,429,291 Okress Oct, 21, 1947 Certicate of Correction Patent No. 2,509,951 May 30, 1950 HOMER G. ANDERSON It is hereby certified that errors appear in the printed specification of the above numbered patent requiring correction as follows:

Column 4, line 37, after lead-in insert conductor; line 40, after the Word cathode insert a semi-colon; line 53, after one insert of which 'is connected to one;

and that the said Letters Patent should be read with these corrections therein that the same may conform to the record of the case in the Patent Oliice. Signed and sealed this 29th day of August, A. D. 1950.

THOMAS F. MURPHY,

Ageia tant Gommz'ssioner of Patents.

Certicate of Correction Patent No. 2,509,951 May 30, 1950 HOMER G. ANDERSON It is hereby certified that errors appear in the printed specification of the above numbered patent requiring correction as follows:

Column 4, line 37, after lead-in insert conductor; line 40, after the word cathode insert a semi-colon; line 53, after one insert 0j which 'is connected to one;

and that the seid Letters Patent should be read with these corrections therein that the seme may conform to the record ofthe case in the Patent Office. Signed and sealed this 29th dey of August, A. D. 1950.

THOMAS F. MURPHY,

Ags/etant Oommz'asz'oner of Patents. 

